DS12885S+;DS12C887A+;DS12885T+;DS12885N+;DS12885+;中文规格书,Datasheet资料

General Description

The DS12885, DS12887, and DS12C887 real-time clocks (RTCs) are designed to be direct replacements for the DS1285 and DS1287. The devices provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed static RAM (113 bytes in the DS12C887 and DS12C887A). The DS12887 integrates a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS12C887 adds a century byte at address 32h. For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The devices also operate in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of V CC . If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin-cell battery can be connected to the V BAT input pin on the DS12885 to maintain time and date operation when primary power is absent. The device is accessed through a multiplexed byte-wide interface, which sup-ports both Intel and Motorola modes.

Applications

Embedded Systems Utility Meters Security Systems

Network Hubs, Bridges, and Routers

Features

?Drop-In Replacement for IBM AT Computer Clock/Calendar ?RTC Counts Seconds, Minutes, Hours, Day, Date,Month, and Year with Leap Year Compensation Through 2099?Binary or BCD Time Representation

?12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode ?Daylight Saving Time Option

?Selectable Intel or Motorola Bus Timing ?Interfaced with Software as 128 RAM Locations ?14 Bytes of Clock and Control Registers ?114 Bytes of General-Purpose, Battery-Backed RAM (113 Bytes in the DS12C887 and DS12C887A)?RAM Clear Function (DS12885, DS12887A, and DS12C887A)?Interrupt Output with Three Independently Maskable Interrupt Flags ?Time-of-Day Alarm Once Per Second to Once Per Day ?Periodic Rates from 122μs to 500ms ?End-of-Clock Update Cycle Flag ?Programmable Square-Wave Output

?Automatic Power-Fail Detect and Switch Circuitry ?Optional 28-Pin PLCC Surface Mount Package or 32-Pin TQFP (DS12885)?Optional Encapsulated DIP (EDIP) Package with Integrated Crystal and Battery (DS12887,DS12887A, DS12C887, DS12C887A)?Optional Industrial Temperature Range Available ?Underwriters Laboratory (UL) Recognized

DS12885/DS12887/DS12887A/DS12C887/DS12C887A

Real-Time Clocks

______________________________________________Maxim Integrated Products

1

19-5213; Rev 4; 4/10

For pricing, delivery, and ordering information,please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at https://www.sodocs.net/doc/3511903144.html,.

Pin Configurations and Ordering Information appear at end of data sheet.

D S 12885/D S 12887/D S 12887A /D S 12C 887/D S 12C 887A

Real-Time Clocks 2_____________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Voltage Range on V CC Pin Relative to Ground.....-0.3V to +6.0V Operating Temperature Range https://www.sodocs.net/doc/3511903144.html,mercial (noncondensing).............................0°C to +70°C Operating Temperature Range ...................................................Industrial (noncondensing)...............................-40°C to +85°C Storage Temperature Range

EDIP..................................................................-40°C to +85°C PDIP, SO, PLCC, TQFP ..................................-55°C to +125°C

Lead Temperature (soldering, 10s).................................+260°C (Note:EDIP is hand or wave-soldered only.)Soldering Temperature (reflow)

PDIP, SO, PLCC............................................................+260°C TQFP.............................................................................+245°C

DC ELECTRICAL CHARACTERISTICS

DS12885/DS12887/DS12887A/DS12C887/DS12C887A Real-Time Clocks

AC ELECTRICAL CHARACTERISTICS

D S 12885/D S 12887/D S 12887A /D S 12C 887/D S 12C 887A

Real-Time Clocks 4_____________________________________________________________________

Motorola Bus Read/Write Timing

Intel Bus Write Timing

DS12885/DS12887/DS12887A/DS12C887/DS12C887A

Real-Time Clocks

_____________________________________________________________________5

Intel Bus Read Timing

IRQ Release Delay Timing

Power-Up/Power-Down Timing

D S 12885/D S 12887/D S 12887A /D S 12C 887/D S 12C 887A

Real-Time Clocks 6_____________________________________________________________________

POWER-UP/POWER-DOWN CHARACTERISTICS

CAPACITANCE

DATA RETENTION

Note 1:RTC modules can be successfully processed through conventional wave-soldering techniques as long as temperature

exposure to the lithium energy source contained within does not exceed +85°C. However, post-solder cleaning with water-washing techniques is acceptable, provided that ultrasonic vibrations are not used to prevent crystal damage.

Note 2:Limits at -40°C are guaranteed by design and not production tested.Note 3:All voltages are referenced to ground.Note 4:All outputs are open.

Note 5:Specified with CS = DS = R/W = RESET = V CC ; MOT, AS, AD0–AD7 = 0; V BACKUP open.

Note 6:Applies to the AD0 to AD7 pins, the IRQ pin, and the SQW pin when each is in a high-impedance state.Note 7:The MOT pin has an internal 20k Ωpulldown.

Note 8:Measured with a 32.768kHz crystal attached to X1 and X2.Note 9:Guaranteed by design. Not production tested.Note 10:Measured with a 50pF capacitance load.

DS12885/DS12887/DS12887A/DS12C887/DS12C887A

Real-Time Clocks

Typical Operating Characteristics

(V CC = +5.0V, T A = +25°C, unless otherwise noted.)

OSCILLATOR FREQUENCY

vs. V CC

D S 12885 t o c 02

V CC (V)

F R E Q U E N C Y (H z ) 5.3

5.04.8

32768.10

32768.2032768.3032768.4032768.5032768.6032768.7032768.00

4.5

5.5

I BAT1 vs. V BAT vs. TEMPERATURE

V BAT (V)

I B A T (n A )

3.8

2.8

3.0

3.3

3.5200

300

250

150

2.5

4.0

Functional Diagram

D S 12885/D S 12887/D S 12887A /D S 12C 887/D S 12C 887A

Real-Time Clocks 8_____________________________________________________________________

Real-Time Clocks

_____________________________________________________________________9DS12885/DS12887/DS12887A/DS12C887/DS12C887A

D S 12885/D S 12887/D S 12887A /D S 12C 887/D S 12C 887A

Real-Time Clocks 10____________________________________________________________________

分销商库存信息:

MAXIM

DS12885S+DS12C887A+DS12885T+

DS12885N+DS12885+DS12885S+T&R DS12885Q+T&R DS12885SN+T&R DS12885QN+T&R DS12885TN+DS12885SN+DS12885QN+